Eggs and cholesterol: the 2020 study of 1.7 million people.

Claim

EGGS AND CHOLESTEROL?

Catch

ALL OBSERVATIONAL

Verdict

LOOKS FINE ASK YOUR DOCTOR

The study: Drouin-Chartier and colleagues combined three large US prospective cohorts — the Nurses' Health Study (83,349 women, 1980–2012), Nurses' Health Study II (90,214 women, 1991–2013) and the Health Professionals' Follow-Up Study (42,055 men, 1986–2012) — with an updated meta-analysis of prospective cohort studies. Cohort analyses covered 215,618 participants free of cardiovascular disease, type 2 diabetes and cancer at baseline, followed for up to 32 years (5.54 million person-years), with 14,806 incident cardiovascular disease cases. The meta-analysis pooled 33 risk estimates covering 1,720,108 participants and 139,195 cardiovascular disease events.

The finding: eating one additional egg per day was not associated with cardiovascular disease risk. Pooled relative risk 0.98 (95% CI 0.93 to 1.03; I² = 62.3%). The same held for coronary heart disease (0.96, 0.91 to 1.03) and stroke (0.99, 0.91 to 1.07). In the three cohorts, one or more eggs per day versus fewer than one per month gave a hazard ratio of 0.93 (95% CI 0.82 to 1.05). Most participants ate between one and fewer than five eggs a week. The result was not uniform across regions: US cohorts 1.01 (0.96 to 1.06), European cohorts 1.05 (0.92 to 1.19), and Asian cohorts an inverse association, 0.92 (0.85 to 0.99). A separate 2020 dose-response meta-analysis of 39 studies and nearly 2 million people reached a similar direction, finding intake of up to six eggs per week inversely associated with CVD events.

The catch, part one — it is all observational. There is no randomized trial here, and there is not likely to be one: you cannot randomize people to eat eggs for three decades. The researchers flagged the confounders explicitly. People who ate more eggs had a higher body mass index, were less likely to be on statins, and consumed more red meat. The null result appears after adjusting for those lifestyle and dietary factors — which is precisely what an observational design cannot do cleanly. Heterogeneity was also substantial (I² = 62.3% for CVD, 71.5% for stroke), and the direction flipped between continents.

The catch, part two — the advice did not fully reverse. The American Heart Association's 2020 science advisory noted that while observational evidence "generally does not indicate a significant association" between dietary cholesterol and cardiovascular disease risk, most meta-analyses of intervention studies associate cholesterol intakes above current average levels with raised total and LDL cholesterol. The AHA's guidance is to focus on dietary patterns rather than a single food. And the yolk is still worth counting: one large egg contains roughly 186 mg of cholesterol (USDA FoodData Central). For most people eggs fit fine; if you have high cholesterol or diabetes, that is a conversation for your doctor, not a headline.

SOURCES

1. Drouin-Chartier JP, Chen S, Li Y, Schwab AL, Stampfer MJ, Sacks FM, Rosner B, Willett WC, Hu FB, Bhupathiraju SN. "Egg consumption and risk of cardiovascular disease: three large prospective US cohort studies, systematic review, and updated meta-analysis." BMJ. 2020;368:m513. DOI: 10.1136/bmj.m513. PMID 32132002. PMCID PMC7190072.
2. Carson JAS, Lichtenstein AH, Anderson CAM, et al. "Dietary Cholesterol and Cardiovascular Risk: A Science Advisory From the American Heart Association." Circulation. 2020;141:e75–e82. DOI: 10.1161/cir.0000000000000743. PMID 31838890.
3. Li Y, et al. "Egg consumption and cardiovascular risk: a dose-response meta-analysis of prospective cohort studies." Eur J Nutr. 2020;59(3):1063–1073. DOI: 10.1007/s00394-020-02345-7. PMID 32865658. PMCID PMC8137614.
4. USDA FoodData Central, "Egg, whole, raw, fresh" (FDC ID 171287).

Disclaimer: For information only, not medical advice. This is observational research, so it shows a lack of association, not proof of safety. If you have high cholesterol, diabetes, or cardiovascular risk factors, talk to your doctor about how many eggs are right for you.